Electric relay



March 18, 1941. H. w. WILLIAMS ETAL 'ELECTRIC RELAY Filed Jan. l2, 1939 ff m M w 4 la INVENTORS Haro/dNt/l'/fam ana/.DoglYa/d/v. aum.

TOEY WITNESSES:

Patented Mar. 18, 1941 UNITED STATES PATENT OFFICE Baum, Ridgewood, N.

J., assignors to Westinghouse Electric Elevator Company, Jersey City, N. J., a corporation of Illinois Application January 12, 1939, Serial No. 256,560

5 Claims.

Our invention relates to electric relays and contactors, and more particularly to the operation of the armatures of such relays and contactors.

In the operation of electrical devices such as relays, contactors .and switches as heretofore cons-tructed considerable difficulty has been encountered because of the noise caused by the blows struck by the armatures against the cores .to which they are attracted, and also by reason of the tendency of the armatures -to bounce when they reach their full open or full closed positions. When the impact of the `armature against the core of a relay causes .a bounce, it often causes excessive arcing and wear on'the contact mem- -bers of the switches operated by the armature.

The noise and bounce are particularly objectionable where the devices lare mounted upon heavy slate panels or other rigid structures. In many instances Athe heavy blow struck by the armature is transmitted to the whole panel and the supporting structure like the blow of a hammer on the panel. In some cases it has been found that the armatures strike .the cores so hard that vibration may be felt in the angle iron frame supports for the panels.

Therefore, it is an object of our invention to provide a relay or contactor in which the noise and bounce resulting from the operation of the armature shall be eliminated as nearly las possible.

Another object is to provide a relay or contactor in which the contact members operated thereby shall be free from excessive arcing and wear.

For a better understanding of our invention, reference may be had to the accompanying drawing, in which:

Figure 1 is a top plan view of a relay or contactor constructed in accordance with our invention,

Fig. 2 is a View in side elevation of the relay or contactor illustrated in Fig. 1,

Fig. 3 is an enlarged detail View in side elevation of the friction device on .the upper end of the stop rod in the relay illustrated in Figs. 1 and 2, and

Fig. 4 is -a View in end elevation of the friction device shown in Fig. 3.

Referring more particularly .to the drawing, we have illustrated a rel-ay or contacter I as comprising a core I I, ya coil I2 for energizing the core and an armature I3 for operation by the core. The core I I is seated in an .armature base I5 and both parts are retained in correct position on a panel I4 by a cap screw I6 which passes upwardly through the panel, the armature base and into the lower end of theA core. The coil I2 is disposed around the core II and is retained in position thereon by a suitable nut I'I.

The armature base has a pair of side wings or arms I8 and I9 that extend upwardly along the sides of the core I2 to provide a pivotal mounting for the armature I3. The armature is provided with a pair of downwardly extending side arms or wings 2l and 22 that embrace the upwardly extending arms I 8 and I9 on the armature base and are pivotally mounted thereon by a pivot pin 23 disposed in transverse holes through the arms of the armature and the arma- .ture base. The pivot pin is located near the rear end of the armature so that the front end of the armature may move into and out of ensagement with the core when the core is energized and deenergized.

The rear portion 24 of the armature is bent downward slightly and is provided with a hole in which the upper end of a tension spring 25 ls hooked. The lower end of the spring is hooked through the upper end of an eye-bolt 26, the lower end of which passes through the panel I4 and is secured therein by a pair of nuts 21. The spring 25 biases the armature I3 away from the core II and is so selected as to strength that, when the core II is energized, its magnetic pull will overcome the tension of the spring and cause the armature to close quickly against the core.

A main iinger board 30 and an auxiliary linger board 3 I, both of insulating material, are mounted upon and secured to the upper surface of the armature .by a plurality of rivets 32 for use in supporting and operating contact finger arms when the armature is attracted by or released by the core.

A main contact nger 33 is mounted upon the main finger board 30 by a tubular rivet 34 and a pivot pin 35. The tubular rivet 34 is rigidly mounted in the finger board and the right-hand end of the main finger is loosely disposed thereon so that the left-hand end of the nger may move a short distance with reference to the iinger board while the right-hand end pivots on the rivet. The pivot pin 35 is disposed upwardly through the left-hand end of the finger board and through a hole in the main finger. A nut 31 and washer 38 are disposed on the free end of the pivot pin to maintain a spring 39 in compression between the washer and the upper face of the main linger. Inasmuch as the head of the pin is disposed on the underside of the iinger board,

the compression spring biases lthe linger against the board.

A lContact member 43 of extmded copper is fixed on the lett-hand end of the contact nnger by a machine screw 4I in position to engage a cooperating main contact member 42 when the armature is released by the core vand is biased away therefrom by the tension spring 25. The contact member 42 is supported in 4a U-shaped base of strap copper or other conducting material by means of a screw bolt 44. The lower end of the U base rests on the slate panel I4 and is secured in position thereon by means of a bolt 45 and a placement clip 4G.

By means of this construction it will be seen that when the armature is released by the core, the tension of the spring 25 will cause it to move to its open position, thereby moving the finger arm 33 to slap the contact member 40 down on the contact member 42, thus closing the main contact members. The compression spring 39 on the pivot pin35 will permitzthe rear endr of thev armature to move past the point where the contact members engage, thereby maintaining a force against the closed contact membersto keep them in good contact while the armature is open. The main ccntact memberv42 may beconstructed of any suitable material such as a compound of copper and carbon, or carbon and graphite.

If the main contact members are provided for carrying a heavy load they may be provided with an arc suppressing horn 41 and a blowout coil 48, the blowout coil being wound around one arm of the U strap'43 and having its one end connected to thev horn'and its other end connectedto asuitable lead-in connector 49. A pair of blowout shieldsv I and 52- are provided for shieldingthe arcing to the arc suppressing horn. The shields are mounted on the sides of the main contact member 42 between the upper ends of thev U strap,

and are retained in position by the screw bolt 44 and alower screw bolt 53. The line 54 in the upper left-hand corner of Fig. 2 represents the point wherethe shield 52 is broken away to permit a view ofthe main contact members. A conducting cable 55 is provided for electrically connecting the main nger 33- with the circuit it is to control'. The left-hand end of the cable is connected to the finger by a screw EB-and its righthand end is connectedto a lead-in connector 51 disposed in thefpanel I4.

The mainboard 3i) andthe auxiliary board 3I maybe provided with as many additional contact fingers for operating additional pairs of contact members as may be desired, but only one auxiliaryfiinger Iii] is illustrated as secured to the board 3l by a pivot pin, 6I and. maintained in position by a compression spring 62. A ilexible conductor 63 is connected to the auxiliary linger and has its lower end attached to a lead-in pin 63a, thus providing an electrical connection for the auxiliary finger. A contact member 64 is disposed on the free end of the contact finger in position to engagea cooperating contact member 65 mounted on-a supporting stud 66, the lower end of which is imbedded in the panel I4 and held there by means of a lead-in pin 91. A nut 68 on the stud 66 permits the Contact member 65 toV be easily adjusted to any desired height for engagement by the contact member 64.

In the operation of relays and contactors of the kind illustrated in the drawing, the armature strikes a heavy blow ,againstv its core when the core is energized to attract ity thereto. The heavy blowcreates unnecessary noise and in many inposed in a cylindrical chamber 'I3 in the armature i 1 with its neck 'II extending outwardly through a restricting flange 'I4 on the front end of the chamber 73. As illustrated in the drawing, the chamber or counterbored hole 'I3 is deeper than the thickness of the pole piece head I2 so as to permit the pole piece to move forward and backward in the chamber. The pole piece may be in serted in the chamber T3 before the auxiliary linger board 'II is mounted thereon. When the finger board'is riveted to the armature, it closes the rear end of the chamber 'I3 and acts as a limiting and retaining rear wall forthe oating pole piece.

Inasmuch as the floating pole face is constructed of magnetic material, it strikes the core in advance of the armature when the core is energized and reduces the noise of operation. We are not entirely clear as tothe theory of what takes place during the operation, but we know that the construction described will reduce the noiseof operation.

It may be that, when the coil I2 is energizedto cause-the core to attract the armature, the floating pole face being lighter than the armature and not biased away from the core, moves forward ahead of the armature toward the core under the magnetic attraction of the core until its movement relative to thearmature is stopped by the flange 14. Next the armature and the oating pole piece move toward the core as one body. Ihen as the armature approaches close to the energized core, the pole piece hits the core rst and is stopped from further movement but the armature continues its forward movement tothe core, thus pushing the cylinder forward on the oating pole piece and separating the flange 'I4 on the armature from the flange I2 on the pole piece. The relative movement of the armature and the pole piece is not visible to the eye but is estimated to. be about gig".

Apparently, approximately the total ilux set up by the coil on the core passes through the flanges on the armature and the pole face as they separate, thereby exerting a strong magnetic pull whichtends to absorb the inertia of the armature and prevent it from over-traveling to any appreciable extent, and thus providing a magnetically elastic member at this point resulting in the very quiet operation of the armature. We have found in actual practice that the only noise present when the armature with its oating pole is attracted to the core is -a slight tap as thepole face hits the core. Regardless of whether or not this theory of operation is correct, if the construction illustrated and described is used, it will result in almost noiseless armature operation.

In many relays and contactors of thecharacter illustrated, it has been found that the operation of the armature is liable to result in a certain amount of bounce when the armature strikes the core, with the result that the contact members controlled by the closing movement of the armature will bounce or vibrate and thus cause arcing and wear. rIhis arcing and wear may also occur when the armature moves to its full open position with Vsnap enoughl to cause 'some degree of bounce.

Even though the movable pole face construction provided has eliminated the heavy blows struck by the armature,'some bounce may remain in the opening and closing operation of the armature. Therefore, we have provided means for further reducing the amount of bounce as the armature strikes the core and also when the armature moves to its full vopen position. This construction comprises a stop rod mounted on the panel I4 and a friction device 8| for connecting the free end of the armature and the stop rod.

The lower end of the stop rodk is movably mounted in the panel |4 and extends therethrough. A lower washer 82 and an upper washer 83 are fastened onthe stop rod to limit its longitudinal movement in the panel. A sleeve 84 is disposed on the stop rod between the washers 82 and 83 to space themapart the predetermined distance it is desired to have the rod operate with lost motion connection in the panel. A pair of nuts 85 and 86 are disposed on the rod to hold the washers and spacing sleeve in the desired position on the rod. With this construction it is seen that the rod has a lost motion connection with the panel and is permitted to move up and down in the panel in the space dened by the washers 82 and 83. The face of each of the washers 82 and 83 may be provided with a soundproong material 8`| toprevent any noise when the rod is stopped by the panel.

The free end of the armature is provided with an extended portion 89 that is bent downwardly in position to be connected to the stop rod 80 by the friction device 8|. The friction device 8| (Figs. 3 and 4) comprises a U-shaped strap member 90, a friction block 9|, a resilient member such as a compression spring 92, a pair of friction washers 83 and 94 and a compression bolt 95.

The U member 90 is seated on the extended free end of the armature and is firmly secured thereto as by welding at 91 so that it becomes practically a part of the end of the armature. The upper end of the stop rod extends upwardly through a hole 98 that passes through the armature end and the bottom of the U-shaped member 90. The friction block 9| is seated inside the U- shaped member 90 and its lower end is firmly screwed on the upper end of the stop rod extending through the hole 98.

In order to supply a. predetermined amount of friction between the U-shaped member 90 and the stop rod, the block 9| is provided with a centrally-disposed transverse slot |00 which permits it to straddle the bolt transversely mounted in the outer ends of the U-shaped member 90. The friction washers 93 and 94 may be constructed of suitable plastic material such as is sold under the trade-mark Micarta and are mounted on the bolt 95, one on each side of the block 9|. A spacing sleeve |0| is disposed between the head of the bolt 95 and the washer 93. A similar spacing sleeve |03 is mounted between the washer 94 and a spring end member |04 on the bolt. The spring 92 is disposed on the bolt and is held between the spring-end member |04 and a spring-end |05 mounted on the outer end of the bolt by means of an adjustable nut |06. The sleeves |0| and |03 are slidably disposed in the upper end of the U-shaped member 90, hence it will be apparent that the nut |06 may be rotated to cause the compression spring 92 to apply sufficient pressure to the friction washers 93 and 94 disposed against the sides of the block as to give the desired amount of friction between the free end of the armature and the stop rod. If it is desired to decrease the amount of friction, the nut |06 may be loosened, and, on the other hand, if it is desired to increase the amount of friction, the nut |06 may be tightened to effect the increase.

When the armature is attracted to the core by energization of the coil l2, it will be apparent that the friction of the friction washers against the friction block will cause the stop rod 80 to move downwardly in the panel I4 until the stop washer 83 comes into contact with the panel. When this point is reached, further downward movement of the rod is prevented, and this causes the friction device to come into play. As the armature continues its movement toward the core the friction washers slide along the friction block 9| with the amount of friction governed by the setting of the compression spring 92. Inasmuch as the washers are connected to the armature through the bolt 95 and the U-shaped member 90, the friction set up in the friction device brakes or slows down the movement of the armature after the stop rod comes to rest. The stop washer 83 should be so disposed on the stop rod that the friction device becomes effective just as the armature engages the face of the core and at just that time which will prevent any bounce on the armature.

The limiting washer 82 on the lower end of the stop rod shouid be so ylocated thereon Ias to move into engagement with the lower face of the panel |'4 as the armature nears its fully open position, so that further movement of the armature towards its open position will cause the friction washers to slide along the friction block and return to their starting point. This operation will also apply la bnaking effect to the armature as it reaches its fully open position, and, at the same time, will reset the stop rod and friction device for again applying a braking effect to the armature when it moves to its closed position under the energization of the coil I2. It will be evident that the stop rod may be connected to the panel I4 by any other lost-motion connecting means which lwill permit it to move freely a predetermined distance before causing the friction device to become effective.

By reason of the apparatus described it can be seen that we have provided a relay or contactor in which the noise and bounce are practically eliminated, with the result there will be little arcing and wear of the contact members operated by the armature. It will also be apparent that the construction of the floating pole face and the friction device are simple and inexpensive to manufacture, assemble and maintain in operation.

Although we have illustrated and described only one specific embodiment of our invention, it is yto be understood that many changes therein and modifications thereof may be made without departing from the spirit and scope of our invention.

We claim as our invention:

l. In a contactor or relay, a base, a core mounted on the base, means for energizing the core, an armature pivotally supported on the base with one end in position to be attracted to the armature when it is energized, an auxiliary pole piece movably mounted in the core engaging face of the armature to strike the core ahead of the armature when it is attracted to the core, to

lessen the striking blcwof fthe armature, and a friction device connected between Vthe core-engaging end of the armature. and the` base to prevent bouncing of the armaturev when it strikes the core'.

2. 'In a contacter or relay, a base, a core mounted on the base, means for energizing the core, an armature pivotally supported on the base with one end in position toI be attracted .to the armature when it is energized'an auxiliary pole piece moya-bly mounted in the core engaging face of the armature tovstrike the core ahead of the armature'when it is attracted to the core, to lessen the striking blow of the armature, a friction rod connected to the base by a lost-motion connection, and' a friction device mounted on the free end of thearmature in position to engage the free end of .the nod to retard the inal closing and the 'final opening movements of the armature when operated by the core.

3. In an electrical device, a base, a magnetiz-V able core mounted on the base, an armature, means for pivotally supporting the armature on the base in position for its free end to be attracted to the core, means for biasing the armature away from the core, mea-ns for energizing the core lto attract the armature thereto, a friction device connected to the freev end of the armature, and a lost-motion connectorfor connecting the friction device .to the base to brake the nal closing movement of the armature just before it engages the core when it is attracted by the energiZati-on of the core and for braking the final opening movement of the yarmature when it is released by deenergization of the core.

4. In an electrical device, a base, a magnetizable core mounted on the base, an armature, means for pivot-ally supporting-the armature on the base in position for its free end to be attracted to the core, means for biasing thevarmature away from the core, means for energizing the core to attract the amature thereto, a friction rod, a friction device connected to the free end of the armature for frictionally engaging one end of the friction rod, and a lost-motion connector for connecting the other end of the friction rod to the base to limit the movement of the friction nod to a predetermined distance, whereby the` rod will move with the armature in its intermediate travel but will stop its movement as .the armature approaches the end of its travelin either opening or closing to cause the friction device to retard .the final movement of the armature and prevent bounce.

5'. .In an electrical device, a base, a magnetizable lcore mounted on the base, an armature, means for pivotally supporting the armature on the base in position for its free end to be attracted to the core, means for biasing the armature away 'from the core, means for energizing the core to attract the free end of the armature thereto, a riction rod having its one end Inova-bly disposed in the base and its other exten-ding toward the free end of the amature, a pair of friction washers, means for supporting the friction wlashers on the free end of the armature in position to embrace the friction rod, resilient means for biasing the washers into frictional engagement with the rod, and a lost motion connector disposed on the base yend :of the rod for limiting the movement of the rod with reference to the base to a predetermined distance to cause the washers to frictionally slide yon the rody for braking the movement of the armature and thereby keep it from bouncing as it reaches its full closed or open position.

HAROLD W, WILLIAMS.

DONALD H. BAUM. 

